Epoxy resin composition for fiber-reinforced composite material, prepreg and fiber-reinforced composite material

Abstract

In an epoxy resin composition, per 100 parts by mass of an epoxy resin component containing from 60 to 85 parts by mass of N,N,N′,N′-tetraglycidyldiaminodiphenylmethane resin (A) having a viscosity at 50° C. of 6000 mPa·s or less and from 15 to 40 parts by mass of a liquid bisphenol A epoxy resin (B) having a viscosity at 25° C. of 20000 mPa·s or less, from 8 to 15 parts by mass of a thermoplastic resin (C), from 2 to 10 parts by mass of elastomer microparticles (D) having an average particle diameter of 1000 nm or less, and from 0.5 to 2.5 parts by mass of silica microparticles (E) having an average particle diameter of 1000 nm or less are blended.

The invention claimed is: 
     
       1. An epoxy resin composition for a fiber-reinforced composite material comprising:
 per 100 parts by mass of an epoxy resin component containing from 60 to 85 parts by mass of N,N,N′,N′-tetraglycidyldiaminodiphenylmethane resin (A) having a viscosity at 50° C. of 6000 mPa·s or less and from 15 to 40 parts by mass of a liquid bisphenol A epoxy resin (B) having a viscosity at 25° C. of 20000 mPa·s or less, 
 from 8 to 15 parts by mass of a thermoplastic resin (C), 
 from 2 to 10 parts by mass of elastomer microparticles (D) having an average particle diameter of 1000 nm or less, and 
 from 0.5 to 2.5 parts by mass of silica microparticles (E) having an average particle diameter of 1000 nm or less; 
 wherein a viscosity at 70° C. is 200 Pa·s or less and 50 Pa·s or greater. 
 
     
     
       2. The epoxy resin composition for a fiber-reinforced composite material according to  claim 1 , wherein a minimum viscosity in a curing process is 1 Pa·s or greater. 
     
     
       3. The epoxy resin composition for a fiber-reinforced composite material according to  claim 1 , wherein the thermoplastic resin (C) is polyethersulfone. 
     
     
       4. The epoxy resin composition for a fiber-reinforced composite material according to  claim 1 , wherein the epoxy resin composition is formed by dissolving the thermoplastic resin (C) in the N,N,N′,N′-tetraglycidyldiaminodiphenylmethane resin (A) and/or the liquid bisphenol A epoxy resin (B). 
     
     
       5. The epoxy resin composition for a fiber-reinforced composite material according to  claim 1 , wherein the elastomer microparticles (D) are core-shell microparticles. 
     
     
       6. The epoxy resin composition for a fiber-reinforced composite material according to  claim 1 , further comprising a curing agent (F), wherein the curing agent (F) is diaminodiphenyl sulfone. 
     
     
       7. The epoxy resin composition for a fiber-reinforced composite material according to  claim 1 , wherein the viscosity at 50° C. of the N,N,N′,N′-tetraglycidyldiaminodiphenylmethane resin (A) is from 3000 to 6000 mPa·s. 
     
     
       8. The epoxy resin composition for a fiber-reinforced composite material according to  claim 1 , wherein the viscosity at 25° C. of the liquid bisphenol A epoxy resin (B) is 18000 mPa·s or less. 
     
     
       9. The epoxy resin composition for a fiber-reinforced composite material according to  claim 1 , wherein the average particle diameter of the elastomer microparticles (D) is 500 nm or less. 
     
     
       10. The epoxy resin composition for a fiber-reinforced composite material according to  claim 1 , wherein the average particle diameter of the silica microparticles (E) is from 5 to 100 nm. 
     
     
       11. A prepreg formed by using the epoxy resin composition for a fiber-reinforced composite material described in  claim 1  as a matrix and by impregnating reinforcing fibers with the epoxy resin composition. 
     
     
       12. A fiber-reinforced composite material, the fiber-reinforced composite material being a thermoset product of the prepreg described in  claim 11 .